ipatests: test ipa-backup with different role configurations.
    
    ipa-backup should refuse to execute if the local IPA server does not
    have all the roles used in the cluster.
    A --disable-role-check knob should also be provided to bypass the
    check.
    
    Add an integration test for the new behavior and the knob.
    
    Related: https://pagure.io/freeipa/issue/8217
    Signed-off-by: François Cami <fcami@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Mohammad Rizwan Yusuf <myusuf@redhat.com>